Bioassay-guided fractionation for antifungal effects of Centaurea virgata subsp. sqaurrosa and Centaurea iberica

Centaurea iberica Tren. et Soreng and Centaurea virgata Lam. subsp. squarrosa (Wild) Gugler were collected from Taleghan 80km NW of Tehran – Iran, voucher specimens were identified and deposited at the herbarium of Faculty Pharmacy, Tehran University of Medical Sciences, on the basis of previous antifungal screening in August 2005.

Their aerial parts were air dried and hydro-alcoholic extractions were prepared by percolation and dried by evaporation of solvents. Anti-fungal studies were done on seven pathogenic fungi including Aspergillus niger, Microsporum canis, Microsporum gypseum, Tricophyton mentogrophytes, Epidermophyton floccossum using cylinder tube test method and Sabourau dextrose agar as culture medium for total extract and fractions. The growth of fungi was achieved at 25–35⁰ C after 72–168 hr of incubation [1]. The total extract was fractionated via solvent to solvent extraction with petroleum ether, chloroform, ethyl acetate and water. The most effective fraction was the petroleum ether extract with 0.5%, 1% of dilution for two species respectively. Pre-phytochemical tests showed flavonoids, sterols, terpenoides and saponins for this effective fraction.

Primary spectrometry, IR and ¹H NMR, showed that the major component of the effective fraction could have a sesquiterpene lactone structure.

References: [1] Mitscher, L.A. et al. (1972) Loydia. 35: 157–16.2.